1. Field of the Invention
The present invention relates to an ink-jet printer, in particular, an ink-jet printer capable of accumulating bubbles separated from ink in an ink path and discharging the bubbles.
2. Discussion of Related Art
To assure a reduction in the size (the thickness) of an ink-jet printer, there is a demand for a reduction in the size (the thickness) of a carriage of the printer, in other words, there is a demand that the inkjet printer is constructed in such a way that an ink tank which accommodates ink is not installed on the carriage. To this end, the ink tank needs to be provided outside of the carriage, e.g., on a frame of the printer, and the ink in the ink tank needs to be supplied, via an ink supply tube, to a recording head carried on the carriage.
In the thus constructed ink-jet printer which uses the ink supply tube for supplying the ink from the ink tank to the recording head, the air inevitably permeates through the tube and is consequently dissolved in the ink due to properties or characteristics of the material for constituting the tube. Accordingly, it is needed to perform a so-called air-purging operation. Described in detail, there is provided a storage chamber (accumulating chamber) on the upstream side of the recording head in which bubbles are separated and removed from the ink.
As a technique to remove the bubbles in the ink-jet printer which uses the ink supply tube, there is known an arrangement as disclosed in JP-A-2000-103084 (paragraphs [0026]-[311] and FIG. 1, in particular), for instance. In this arrangement, a manifold (functioning as the storage chamber) is provided above the recording head while an ink tank and a circulating pump are provided on a stationary-position side, and the circulating pump is driven to remove the bubbles.
In the arrangement disclosed in JP-A-2000-103084, however, the ink-jet printer inevitably tends to be large-sized and complicated since it is needed to provide a return tube through which the ink is returned from the circulating pump to the ink tank for circulation.
Further, there is known an arrangement as disclosed in JP-A-2002-240310 (paragraphs [0006]-[0018] and FIG. 5, in particular), for instance. In this arrangement, the air separated as the bubbles in the ink supply tube is accumulated at an upper portion of the ink tank installed on the carriage and is discharged by a discharge pump. After the discharge of the air, the ink tank is fluid-tightly closed by an air-discharging valve.
The applicant of this application made an extensive study to meet a demand for simplification of a structure of an air-discharging valve for discharging the air in the ink-jet printer. As a result of the study, the applicant developed an air-discharging valve device. In the developed air-discharging valve device, a valve member is provided in an air-discharge hole that is a part of an air-discharge passage communicating with a storage chamber, such that the valve member is moved in an axis direction of the air-discharge hole by an operating member for thereby opening and closing the air-discharge passage. Thus, the developed device enables the bubbles in the storage chamber to be easily discharged.
For removing the bubbles in such an air-discharging valve device, it is required, for instance, that the valve member is moved along the axis direction of the air-discharge hole when the recording head is located at a maintenance position which is outside of a recording region where the recording head performs recording.
Accordingly, the following arrangement may be considered: At the maintenance position, the air-discharge hole is closed or capped at its open end by a cap member. For performing the air-purging operation, at the same time when the open end of the air-discharge hole is capped by the cap member, the valve member is moved by an operating member provided on the cap member and having an operating portion for moving the valve member, whereby the air-discharging valve device is placed in a valve-open state.